Detergent compositions for removing silicone grease



United States Patent Office 3,0h9,3fi Patented Dec. '18, 1962 The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to improvements in alkaline detergents for the cleaning of metal surfaces. More particularly the invention concerns alkaline detergent compositions suitable for use in the removal of silicone greases from the surfaces of metal objects as a step in the fabrication of the metal into a finished product having a coating on the surface of the metal.

Prior to the discovery of the invention to be described hereinafter it was particularly difficult to remove silicone grease soils from metal surfaces. Known aqueous alkaline cleaning solutions, particularly those of the hot soak tank type, were generally incapable of cleaning silicone greases from metals regardless of their alkalinity or the type of surface-active additive and alkaline salt detergents employed. The highly lipophilic character of the silicone grease rendered it immune to removal by known aqueous detergent solutions.

The recent greatly increased usage of silicone coating compositions, and the difficulty of removing these coatings by conventional aqueous solutions makes it imperative that an efficient, rapid and inexpensive composition be developed for accomplishing the removal of silicones from metal and other surfaces.

Therefore a primary object of this invention is the development of aqueous alkaline detergent compositions capable of effectively removing silicone grease soils from metal surfaces.

Another object of the invention is the presentation of an alkaline detergent composition for use in aqueous solutions and capable of removing silicone grease soils from the surfaces of ferrous metals and their alloys.

In accordance with the above mentioned objectives it has now been found that cleaners capable of efiiciently removing silicone grease soils from metals can be attained by the addition of specific, stable, anionic and non-ionic types of surface active agents to alkaline salt detergents of high alkalinity. By alkaline salt detergents of high alkalinity is meant those salts or mixtures thereof which when dissolved in suitable amounts of water will produce solutions having a minimum pH of 13.1 and preferably higher.

For an effective cleaning composition, the surface-active agents should consist of suitable amounts of a non-ionic material of the polyoxyalkylene diol type or mixtures thereof and an anionic material of the alkali metal fatty acid soap type. Examples of the polyoxyalkylene diol surface active agents suitable for use are the monobutyl ethers of oxyethylene-oxy 1,2 propylene diols sold commercially as Ucon 50HB-3520 and Ucon SO-HB-S 100. The Ucon 50HB types of oxyethylene-oxy 1,2 propylene diols are compositions covered by US. Patent No. 2,425,845. The specific non-ionic surface active agent used in the working example is Ucon 5 0-HB-3520 which is the monobutyl ether of a mixed ethylene-propylene polyoxyalkylene glycol in which the weight ratio of ethylene oxide to 1,2 propylene oxide is 1:1 and in which the total molecular weight of the butyl derivative is about 2. 3500 or greater. As an example of an alkali metal fatty acid soap type of surface active agent, sodium laurate, sodium oleate or any other similar compound has been found. to be suitable for use in the cleaning composition of this invention.

The following specific examples are given by way of iilustrating preferred embodiments of the alkaline cleaner compositions of this invention. In these examples as elsewhere throughout the specification and claims, all weights and percentages are given in terms of weight unless specifically designated to the contrary.

Example I Component: Percent by weight Sodium orthosilicate 87.6 Ucon 50-HE3520 5.7 Laurie acid 6.7

This composition when used at a concentration of approximately 9.5 ounces per gallon of water at boiling temperature effectively removes silicone grease soils from metal surfaces.

Example II Component: Percent by weight Sodium metasilicate 50.0

Sodium hydroxide 37.6

Ucon 50-HB3520 5.7

Laurie acid 6.7

This composition is used in the same manner as that of Example I.

The sodium orthosilicate and sodium metasilicate of the above examples are anhydrous grade. The lauric acid employed was of the Neo-Fat 11 brand as manufactured by the Amour Chemical Division of Armour and Company. As will be obvious to those skilled in the art, the lauric or other type fatty acids forms the sodium soap in situ on solution of the ingredients in water.

The examples given above illustrate cleaner compositions adapted to give optimum detergency. However, the nonionic content of the cleaners may be varied from 4.5 to 7.5 percent by weight and the fatty acid soap content may be varied from 6.0 to 10.0 percent by weight. The concentration of aqueous solutions of the detergent compositions of this invention may be varied from approximately 8.0 to 12.0 ounces per gallon of water, 9.5 ounces per gallon representing the optimum value.

While the instant invention has been shown and described herein in what are conceived to be the .most practical and preferred embodiments, it is to be recognized that departures may be made therefrom within the scope of the invention, which is therefore not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalents.

What is claimed and desired to be secured by United States Letters Patent is:

1. A silicone grease cleaning composition capable of removing silicone grease soils from metal surfaces consisting essentially of, by weight, of from 4.5 to 7.5 percent of the monobutyl ether of oxyethylene-oxy 1,2 propylene diol in which the weight ratio of ethylene oxide to propylene oxide is 1:1 and in which the total molecular weight of the butyl derivative is greater than about 3500, of from 6 to 10 percent of a water soluble alkali metal fatty acid soap selected from the group consisting of sodium laurate and sodium oleate and the remainder of the composition consisting essentially of a sodium silicate.

2. A silicone grease cleaning composition consisting of, by weight, 87.6 percent sodium orthosilicate, 5.7 percent of the monobutyl ether of oxyethylene-oxy 1,2 propylene diol in which the weight ratio of ethylene oxide to propylene oxide is 1:1 and in which the total molecular weight of the butyl derivative is greater than about 3500 and 6.7 percent lauric acid.

3. A silicone grease cleaning composition consisting of, by weight, approximately 50 percent sodium metasilicate, 37.6 percent sodium hydroxide, 5.7 percent of the monobutyl ether of oXyethylene-oxy 1,2 propylene diol in which the weight ratio of ethylene oxide to propylene oxide is 1:1 and in which the total molecular weight of the butyl derivative is greater than about 3500 and 6.7 percent lauric acid.

4. An aqueous cleaning solution capable of removing silicone grease soils from metal surfaces containing from 6to 10 percent by weight of the cleaning composition of claim 3.

4- References Cited in the file of this patent UNITED STATES PATENTS 2,614,992 Mankowich Oct. 21, 1952 2,615,853 Kirkpatrick Oct. 28, 1952 2,806,001 Pong et al Sept. 10, 1957 FOREIGN PATENTS 716,354 Great Britain Oct. 6, 1954 OTHER REFERENCES Pluronics in Metal Cleaning Formulations, Wyandotte 5. A composition as described in claim 4 having a pH 15 Chem. Corp., pp. 11-13; receivid in U.S. Patent Office of not less than 13.1.

on Jan. 7, 1957. 

1. A SILICONE GREASE CLEANING COMPOSITION CAPABLE OF REMOVING SILICONE GREASE SOILS FROM METAL SURFACES CONSISTING ESSENTIALLY OF, BY WEIGHT, OF FROM 4.5 TO 7.5 PERCENT OF THE MONOBUTYL ETHER OF OXYETHYLENE-OXY 1,2 PROPYLENE DIOL IN WHICH THE WEIGHT RATIO OF ETHYLENE OXIDE TO PROPYLENE OXIDE IS 1:1 AND IN WHICH THE TOTAL MOLECULAR WEIGHT OF THE BUTYL DERIVATIVE IS GREATER THAN ABOUT 3500, OF FROM 6 TO 10 PERCENT OF A WATER SOLUBLE ALKALI METAL FATTY ACID SOAP SELECTED FROM THE GROUP CONSISTING OF SODIUM LAURATE AND SODIUM OLEATE AND THE REMAINDER OF THE COMPOSITION CONSISTING ESSENTIALLY OF A SODIUM SILICATE. 